1. Field of the Invention
The present invention relates to a brake assembly for a motorcycle provided with a hydraulically driven front wheel brake and rear wheel brake, for relational control of the two brakes.
2. Background Art
A motorcycle brake actuation is carried out using a brake lever provided on the handlebar and a brake pedal provided on a step. A braking force is distributed to the front wheel brake and rear wheel brake according to actuation of each of the actuating means.
Japanese Patent Laid-open Publication No. Hei. 7-196068, discloses a brake system using partial electronic control. The brake system of this example is shown in FIG. 7.
A front wheel brake 02 and a rear wheel brake 05 are hydraulic brakes. A lever master cylinder 07 is provided on a brake lever of actuating means, while a pedal master cylinder 012 is provided on a brake pedal 011.
A lever hydraulic system 08 extending from the lever master cylinder 07 is connected to the front wheel brake 02. A pedal hydraulic system 013 extending from the pedal master cylinder 012 is connected to one port of the three port type rear wheel brake 05. A hydraulic circuit 014 branching from the pedal hydraulic system 013 is connected to a secondary master cylinder 010, and the output of the secondary master cylinder 010 is connected to the other 2 ports of the rear wheel brake 05 through a control valve 016.
A brake switch 04 opened and closed by rotation of the other brake lever 06 is provided on the brake lever 06. A pressure sensor 041 for detecting hydraulic pressure is provided in the lever hydraulic system 08. A control unit 031 determines hydraulic pressure to be generated at the secondary master cylinder 010 based on each of the detection signals from the brake switch 040 and the pressure sensor 041, and actuates an actuator 033 via a relay 032, so that the secondary master cylinder 010 generates the hydraulic pressure as determined. These devices constitute an electronically controlled braking system.
When the brake pedal 011 is actuated independently, only the rear wheel brake 05 side is actuated disassociated from the front wheel.
When the brake lever 06 is actuated independently, or at the same time as the brake lever 011, the front wheel brake 02 is actuated by hydraulic pressure of the lever master cylinder 07, and the actuator 033 is actuated based on hydraulic pressure of the lever hydraulic system 08 to generate necessary hydraulic pressure in the secondary master cylinder 010 so that the rear wheel brake is actuated by the control valve 016.
The pedal hydraulic system 013. branches into 2 sections, with pipes leading to the rear wheel brake 05 and to the secondary master cylinder 010, and the control valve 016 is located between the secondary master cylinder 010 and the rear wheel brake 05. This means that the structure has many components and is complicated, and the operation of installing the piping and also maintenance can not be carried out easily.
The layout of the piping is also subject to restrictions, and there is little degree of freedom in the design.